1. Field of the Invention
The invention is related to the field of wireless networks and, in particular, to providing a call waiting distinctive ringback feature to subscribers of a wireless network.
2. Statement of the Problem
If a calling party places a call to a called party, the sounds heard by the calling party when waiting for the called party to answer is referred to as ringback (or ringback tones). The wireless network over which the call is placed provides the ringback to the calling party, which is typically a ringing sound. As an example, the calling party places the call that is routed to a Mobile Switching Center (MSC) in the wireless network that is serving the called party. Responsive to receiving the call, the serving MSC determines the availability of the called party for the call. If the serving MSC determines that the called party is available, then the serving MSC provides ringing to the called party and provides ringback to the calling party. If the serving MSC determines that the called party is busy (i.e., presently on another call), then the serving MSC provides busy tones to the calling party.
If the called party subscribes to call waiting, then the serving MSC does not provide busy tones to the calling party. Instead, the serving MSC provides ringback to the calling party indicating that the called party is not busy and is available for the call. Some MSCs from some vendors are provisioned to provide a distinctive ringback to the calling party indicating that the called party is busy but has call waiting. Distinctive ringback refers to a type of ringback that is associated with call waiting so that the calling party hearing the distinctive ringback can understand that the called party is on another call and has subscribed to call waiting. The distinctive ringback may be a different ring pattern or a different sounding ring. Non-distinct ringback (or regular ringback) on the other hand is a type of ringback that is not associated with call waiting. Non-distinct ringback may include a traditional sounding series of rings.
One problem with present wireless networks is that they may not be able to provide distinctive ringback to subscribers in all areas of their network or when the subscribers are roaming. The ability to provide distinctive ringback depends on how the serving MSC is programmed, wired, or otherwise provisioned. As previously stated, MSCs from some vendors are provisioned to provide distinctive ringback for all calls where the called party is busy and has subscribed to call waiting. Other MSCs from other vendors are not provisioned to provide distinctive ringback at all. Unfortunately, service providers have to obtain MSCs from a certain vendor or vendors in order to provide distinctive ringback. If the service provider obtains MSCs from other vendors, then the service provider will not be able to provide the same type of ringback throughout their network. Also, the service provider may not be able to provide distinctive ringback for roaming subscribers.